I agree that this sauce made the meal. I followed the recipe exactly as written and everyone thought it was a great dish.
This was a really unique decision to cook something that had a tuna dipping sauce, but the sauce was so amazing that it trumped any doubts! I would say the sauce would be amazing if you took the arugula and sauce and made a sandwich. The chicken was good, and really filled you up, but the sauce was the stand out. The only substitution I made was that I used fish sauce instead of an anchovy fillet.